The AEVA branch Scooter - available for any member to borrow - needs a little TLC. It's still working well, it just has a few cosmetic issues. Like the turn signal switch breaking off, the speedo cable failing about 10,000 km ago, and some rust around the gills.

All of this can be fixed with another fun day of tinkering. However, this is a great chance to try something a little more advanced. The bike needs a speedo and some kind of Coulomb counter. It's also a bit, well, slow Perth is pretty good with scooters, as the 70 km/h zones tend to be dual carriageway, so faster vehicles can pass you. But lumbering up hills isn't so fun. So how's about we pimp this ride?

Some time back I put a LiPo booster pack in parallel with the main EV-Power LiFePO4 pack and it hummed along very smartly. The main thing was to limit the sag, so perhaps a battery-controller upgrade is on the cards? There are some pretty schmick e-bike controllers out there capable of delivering 3 kW continuous, which would certainly make this thing move.

I'm happy to build a LiPo battery pack for it - it would be 16s8p using the 5 Ah cells. At these dimensions, the 2.3 kWh pack would never sag. Ever Alternatively we could build a lower capacity pack but just go silly with the controller voltage. Some E-bikes can do 90 km/h on a hub motor, so there's no reason we can't overvolt this little 1.5 kW hub with a new controller. Perhaps 72V?

I can offer my time and experience, as well as some battery box fabrication. We have a few left over LiPo cells from the race bike battery build - perhaps not enough to build a whole battery but certainly a booster. We also need a working dash, so perhaps NevilleH can devise that new Ah meter?

I ran my emax at 60V on the stock controller with no issues. It increased top speed to around 65kph.
I don't think it would be a good idea to increase the top speed past 70kph with a new controller though. With brakes that are not the best and such small wheels it gets a bit iffy!

Given the LiPos don't really sag like the LiFePO4 does, maybe a 14s pack at 40 Ah would be fine. It's only ever experiencing about 60 amps at full load, and at 50 V nominal, that's probably enough to maintain 60 km/h. Best of all the 14s LiPo pack will weigh less.

The cycle life on these cells isn't spectacular, maybe 500 cycles, but I'm sure at these low power levels it could get pushed out to 1000 cycles.

As a bit of an update, the blue E-Max sport bought by the Perth branch is now de-registered. The battery and BMS is up for sale and the proceeds will go back into the Perth branch coffers. I've spent about another $100 on it since, installing the new BMS and re-wiring the balance leads etc.

It would suit anyone in Perth/South West who is keen for a project or just keen to muck around with a 2 kWh battery. The battery has never been mistreated, and it still manages 50 km per charge.

The battery is a set of 32 individual GBS LiFePO4 cells, 20 Ah each, but connected as two in parallel and 16 in series. You can of course pull them apart and put them together however you like.

$500 for the whole lot. Sorry, you have to take the whole lot

Last edited by jonescg on Fri, 17 Jul 2015, 20:28, edited 1 time in total.